Position indicator

ABSTRACT

A single position indicator that can be used with a plurality of different types of position detection systems. The position indicator includes a communication circuit which, in operation, communicates with an outer device, a configuration circuit which, in operation, performs an initial setting process based on a signal from the outer device, a signal generation circuit which, in operation, generates a stylus position signal, and a control circuit. The control circuit, in operation, controls transmission of the stylus position signal based on an initial setting of at least one switch circuit that is set by the initial setting process performed by the configuration circuit, and controls reception of a signal received from the outer device via the communication circuit.

BACKGROUND Technical Field

The present disclosure relates to a position indicator (stylus) for usewith a position detection system.

Description of Related Art

As a position inputting apparatus configured from a position detectionsystem and a position indicator called electronic pen is configured invarious types such as, for example, an electromagnetic coupling type anda capacitive coupling type depending upon the difference in the couplingmethod between a sensor of the position detection system and theelectronic pen.

Even if position inputting apparatus are of the same type, variousconfiguration types are available depending upon the difference betweenthe exchange method of a stylus position signal between the sensor ofthe position detection system and the position indicator and the methodfor exchange of, between the position detection system and the positionindicator, additional information such as operation information of aswitch provided on the position indicator, pen pressure information,identification information of the position indicator and internalstorage data or for exchange of instruction information for changing theaction of the position indicator. Conventionally, a position indicatorcompatible with a position detection system is provided to a user whilea method for a stylus position signal and a method for exchange ofadditional information are restricted to particular methods. Therefore,since it is necessary for a utilizer to have a position indicator forexclusive use for a position inputting apparatus which includes aposition detection system having a similar position detection sensor, itis necessary for the utilizer to carry a plurality of positionindicators and select a suitable position indicator for every positioninputting apparatus.

For example, for a position indicator of the capacitive coupling type, aplurality of configuration types as described below is available. Inparticular, the position indicator of the first configuration type is aposition indicator of a type (passive type) wherein a stylus positionsignal is not sent from the position indicator but a change of energy(or a voltage) induced in a conductor of a sensor of a positiondetection system at a position at which the position indicator isdisposed when alternating electric field energy sent from the sensor ofthe position detection system is supplied to the earth (ground) via theposition indicator and the human body is detected to perform positiondetection (refer to, for example, Patent Document 1 (Japanese PatentLaid-Open No. 2011-3035) and so forth).

Meanwhile, the position indicator of the second configuration type ofthe capacitive coupling type is an improvement of the firstconfiguration type described above in regard to its low sensitivity inposition detection and is a position indicator of the type wherein asignal is received from a sensor of a position detection system and isthen fed back to the sensor after signal processing such as signalenhancement is performed for the received signal (improved type of thepassive type) (refer to, for example, Patent Document 2 (Japanese PatentNo. 4683505) and so forth). In the case of the position indicators ofthe first and second configuration types, additional information istransmitted or exchanged to the position detection sensor using, forexample, a wireless communication circuit.

The position indicator of the third configuration type of the capacitivecoupling type is, different from those of the first and secondconfiguration types described above, a position indicator of theso-called active type wherein the position indicator includes anorigination circuit and an origination signal from the originationcircuit is supplied as a stylus position signal to the positiondetection sensor (refer to, for example, Patent Document 3 (JapanesePatent Laid-Open No. Hei 07-295722) and so forth). Although a sensorpanel of a position detection circuit is used as the position detectionsystem, position detection of a position indicated by the positionindicator is performed from signal intensities of individual conductorswhich receive the origination signal from the position indicator of theactive type.

In the case of such position indicators of the third configuration type,the position indicators are further classified into a plurality of typesincluding a configuration type wherein all of additional information issent to and received from the position detection system together with astylus position signal and another configuration type wherein part ofadditional information is sent and received together with a stylusposition signal while the other additional information is transmittedseparately to a wireless communication circuit provided in the positiondetection system via a wireless communication circuit.

It is to be noted that, although detailed description is omitted, it issimilar to the capacitive coupling type described above that, also inthe electromagnetic coupling type, there exist a plurality ofconfiguration types including a configuration type wherein the positionindicator receives a signal from a sensor of the position detectionsystem by a resonance circuit and the received signal is fed back to thesensor of the position detection system and another configuration typewherein an origination circuit is provided and an origination signalfrom the origination circuit is transmitted to a sensor of the positiondetection system via the resonance circuit as well as a configurationtype wherein additional information is transmitted to a wirelesscommunication circuit which transmits the additional information to awireless communication circuit provided in the position detectionsystem.

PRIOR ART DOCUMENTS PATENT DOCUMENTS

-   Patent Document 1: Japanese Patent Laid-Open No. 2011-3035-   Patent Document 2: Japanese Patent No. 4683505-   Patent Document 3: Japanese Patent Laid-Open No. Hei 07-295722

BRIEF SUMMARY OF DISCLOSURE Technical Problems

Incidentally, in the past, even with position inputting apparatus of thesame capacitive coupling type or electromagnetic coupling type, aposition indicator compatible with a configuration type must be preparedfor each of a plurality of different configuration types as describedabove. However, that a position indicator must be prepared for each ofdifferent configuration types in this manner imposes a burden in termsof the cost on its user and the user must manage the position indicatorsof the plurality of configuration types for compatibility with theposition detection system, which is cumbersome.

It is an object of the present disclosure to solve the problemsdescribed above and provide a position indicator with which a pluralityof configuration types can be utilized singly.

Technical Solution

In order to solve the problems described above, the present disclosureprovides a position indicator, including: a communication circuit which,in operation, communicates with an outer device; a configuration circuitwhich, in operation, performs an initial setting process based on asignal from the outer device, an initial setting of at least one switchcircuit being set by the initial setting process; a signal generationcircuit which, in operation, generates a stylus position signal; and acontrol circuit which, in operation, controls transmission of the stylusposition signal based on the initial setting set by the initial settingprocess performed by the configuration circuit, and controls receptionof a signal received from the outer device.

In the position indicator according to the present disclosure having theconfiguration described above, the configuration circuit performs theinitial setting for the position indicator based on the signal from theouter device received by the communication circuit. This initial settingcan include switching setting of a plurality of configuration types.Further, the control circuit controls transmission of the stylusposition signal on the basis of the initial setting process performed bythe configuration circuit and the signal from the outer device.

Consequently, the position indicator according to the present disclosurecan be configured to be compatible with various types of positiondetection systems.

Advantageous Effect

Since the position indicator according to the present disclosure canadopt, in response to a configuration type of a position detectionsystem, a configuration (mode) compatible with the configuration type,there is no necessity to prepare a position indicator for each of aplurality of position detection systems of different configurationtypes. Therefore, the burden on a user in terms of cost can be reduced.Further, since only it is necessary for the user to prepare a singleposition indicator common to position detection systems of a pluralityof configuration types, an effect is achieved that the necessity forcumbersome management for compatibility with a position detection systemis eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view depicting a conceptual configuration of a positionindicator according to one or more embodiments of the presentdisclosure.

FIGS. 2A and 2B are views illustrating an example mechanicalconfiguration of a position indicator according to one or moreembodiments of the present disclosure.

FIG. 3 is a timing chart illustrating processing actions of a positionindicator according to one or more embodiments of the presentdisclosure.

FIG. 4 is a block diagram of a position indicator according to one ormore embodiments of the present disclosure.

FIG. 5 is a view illustrating pen type table information of a positionindicator according to one or more embodiments of the presentdisclosure.

FIG. 6 is a flow chart illustrating an example of a processing flow of aposition indicator according to one or more embodiments of the presentdisclosure.

FIG. 7 is a flow chart illustrating the example of a processing flow ofa position indicator according to one or more embodiments of the presentdisclosure.

FIG. 8 is a view illustrating an example of a position indicator havinga configuration type that can be configured according to one or moreembodiments of the present disclosure.

FIG. 9 is a view illustrating an example of a position indicator havinga configuration type that can be configured according to one or moreembodiments of the present disclosure and a corresponding positiondetection system.

FIG. 10 is a view illustrating another example of a position indicatorhaving a configuration type that can be configured according to one ormore embodiments of the present disclosure and a corresponding positiondetection system.

FIG. 11 is a timing chart illustrating the example of FIG. 10 .

FIG. 12 is a view illustrating a further example of a position indicatorhaving a configuration type that can be configured according to one ormore embodiments of the present disclosure and a corresponding positiondetection system.

FIG. 13 is a timing chart illustrating the example of FIG. 12 .

FIG. 14 is a view illustrating a still further example of the positionindicator of the configuration type which can be configured by theembodiment of the position indicator according to one or moreembodiments of the present disclosure and a corresponding positiondetection system.

FIG. 15 is a timing chart illustrating the example of FIG. 14 .

FIG. 16 is a view depicting a conceptual configuration of a positionindicator according to one or more embodiments of the presentdisclosure.

FIGS. 17A, 17B, and 17C each illustrate an example of a positionindicator having a configuration type which can be configured accordingto one or more embodiments of the present disclosure.

FIGS. 18A and 18B illustrate examples of a position indicator having aconfiguration type that can be configured according to one or moreembodiments of the present disclosure.

FIG. 19 is a view illustrating an example of a position indicator havinga configuration type that can be configured according to one or moreembodiments of the present disclosure.

DETAILED DESCRIPTION

In the following, embodiments of a position indicator according to thepresent disclosure are described with reference to the drawings. FIG. 1is a view generally depicting a conceptual configuration and aprocessing action of a position indicator 1 of according to one or moreembodiments of the present disclosure and is a view illustrating a statein which the position indicator 1 is positioned on a sensor inputtingface 2 a of a position detection system 2 of the capacitive type.Meanwhile, FIGS. 2A and 2B are views illustrating an example of amechanical configuration of the position indicator 1, wherein FIG. 2A isa partial vertical sectional view and FIG. 2B is a view depicting partof an appearance of the position indicator 1. In the present embodiment,the position indicator 1 is formed such that an appearance thereof has ashape of a bar-like stylus.

Description of Example of Mechanical Configuration of Position Indicatorof Embodiment

The position indicator 1 of the present embodiment includes a bar-likehousing 3. The housing 3 is configured from an insulator portion 31 of ahollow cylindrical shape made of an insulating material, for example, asynthetic resin as depicted in FIG. 2A. In the present embodiment, anouter circumferential face of the insulator portion 31 of the housing 3is covered, at least at a portion thereof at which an operator graspsthe position indicator 1, with a conductor portion 32 made of, forexample, a metal.

In the housing 3, a printed circuit board 40, a battery 5 and a penpressure detection circuit 9 are disposed as depicted in FIG. 2A. Theconductor portion 32 which covers the outer circumferential face of thehousing 3 is, though not depicted, electrically connected to a groundingconductor of the printed circuit board 40.

On the printed circuit board 40, a signal transmission control circuit41, a wireless communication circuit 42, a side switch 43 configuredfrom a pushbutton switch, an identification (ID) memory 44 for storingID information of the position indicator 1, oscillators 45 and 46 whichoutput oscillation signals of frequencies f1 and f2 different from eachother, and wiring patterns such as conductive patterns 47 a to 47 e aredisposed as depicted in FIG. 1 and FIG. 2A. Further, in the presentexample, a power supply switch 48, an LED (Light Emitting Diode) 49 andso forth are disposed as depicted in FIG. 2A. It is to be noted that,while, in FIG. 2A, the conductive patterns 47 a to 47 e areschematically depicted as a single conductive pattern for thesimplification of the illustration, naturally there also is a case inwhich the conductive patterns 47 a to 47 e are configured from aplurality of conductive patterns as occasion demands.

The battery 5 is a supply source of power to electronic circuits andelectronic parts configured on the printed circuit board 40. The penpressure detection circuit 9 is configured as a variable capacitor whichdemonstrates a capacitance corresponding to a pen pressure applied to acenter electrode 7 which configures a core member.

The wireless communication circuit 42 configures an example of acommunication circuit (first communication circuit) in the presentdisclosure and has a transmission circuit which is an example of a firsttransmission circuit and a reception circuit which is an example of afirst reception circuit which receives a signal from the positiondetection system. In the present embodiment, the wireless communicationcircuit 42 is configured as a wireless communication circuit whichcomplies with the Bluetooth (registered trademark) standard of ashort-range wireless communication standard. The wireless communicationcircuit 42 is connected to the signal transmission control circuit 41.It is to be noted that the wireless communication circuit 42 may notcomply with the Bluetooth but may be, for example, that by infraredcommunication, or a wireless communication circuit which complies withthe Wi-Fi (registered trademark) standard may be used.

The side switch 43, ID memory 44 and pen pressure detection circuit 9individually configure an additional information generation circuit. Theside switch 43 supplies on or off information thereof as an example ofadditional information to the signal transmission control circuit 41.The ID memory 44 outputs identification information (ID: Identification)of the position indicator 1 stored therein as an example of additionalinformation to the signal transmission control circuit 41 in response toa readout request from the signal transmission control circuit 41. Thevariable capacitor configured from the pen pressure detection circuit 9demonstrates a capacitance variation in response to a value of a penpressure applied to the center electrode 7 which configures the coremember, and the signal transmission control circuit 41 generates penpressure information as an example of additional information on thebasis of the capacitance.

The oscillators 45 and 46 generate alternating signals for forming astylus position signal to be sent from the position indicator 1 of thepresent embodiment and supply the generated alternating signals to thesignal transmission control circuit 41. In the present embodiment, theoscillator 45 generates an alternating signal of the frequency f1 andthe oscillator 46 generates an alternating signal of the frequency f2different from the frequency f1. The signal transmission control circuit41 generates different stylus position signals on the basis of theoscillator 45 and the oscillator 46. In particular, the signaltransmission control circuit 41 cooperates with the oscillator 45 andthe oscillator 46 to configure a circuit for generating a stylusposition signal and configure two origination circuits. The signaltransmission control circuit 41 uses one of the two generated stylusposition signals as a stylus position signal to be sent from theposition indicator 1. It is to be noted that, in place of theoscillators 45 and 46, a plurality of origination circuits whichgenerate and originate stylus position signals for a plurality ofposition indicators of different configuration types of the active typehereinafter described may be provided and are selectively controlled bythe signal transmission control circuit 41.

Further, in the present embodiment, the battery 5 is configured suchthat it is accommodated in the housing 3 in such a manner as depicted inFIG. 1 and FIG. 2A, and a power supply voltage for an electronic circuitsuch as the signal transmission control circuit 41 on the printedcircuit board 40 is generated by the battery 5. In FIG. 2A, a terminal52 is a terminal electrically connected to the power supply circuit onthe printed circuit board 40. A positive side electrode 51 of thebattery 5 contacts with and is electrically connected to the terminal52. Though not depicted, a negative side electrode of the battery 5 isconnected directly to the grounding conductor of the printed circuitboard 40 or is pressed against and contacted with a terminal which isconnected to the grounding conductor of the printed circuit board 40 viathe conductor portion 32 of the housing 3 and is elastically displaced.

An operation element 48 a of the power supply switch 48 disposed on theprinted circuit board 40 is provided for operation from the outsidethrough an opening provided in the housing 3 as depicted in FIG. 2B. Ifthe user slidably moves the operation element 48 a, then the powersupply switch 48 can be switched on or off. It is to be noted that,while also a power supply circuit for generating a power supply voltagefrom the voltage of the battery 5 when the power supply switch 48 is onis formed on the printed circuit board 40, it is omitted for simplifiedillustration in FIGS. 1 and 2A.

One end portion side in a direction of a center axis of the insulatorportion 31 of a hollow cylindrical shape configuring the housing 3 isformed as a tapering portion 33 which tapers gradually as depicted inFIG. 2A. To an outer circumference side of the tapering portion 33, aperipheral electrode 6 made of, for example, an annular conductive metalis attached. The peripheral electrode 6 and the conductor portion 32 onthe outer circumferential surface of the housing 3 are isolated fromeach other by the insulator portion 31 interposed therebetween.

As schematically depicted in FIG. 1 , the peripheral electrode 6capacitively couples with the position detection system 2 to configure,in the present embodiment, a reception circuit for a signal from theposition detection system. The peripheral electrode 6 is electricallyconnected to the conductive pattern 47 a of the printed circuit board 40by a lead conductor member 61 extending through the insulator portion31. The conductive pattern 47 a is connected, in the present example, toan input terminal of the signal transmission control circuit 41.

Further, in the present embodiment, the center electrode 7 configuredfrom a bar-like member having conductivity is disposed such that one endside thereof projects to the outside from the hollow portion of thetapering portion 33 of the housing 3. This center electrode 7 serves asa core member configuring a pen tip of the position indicator 1 of ashape of a pen.

The center electrode 7 configures, in the present embodiment, an exampleof a second transmission circuit for transmitting a stylus positionsignal and is configured such that an end portion on the opposite sideto the side on which it projects to the outside is electricallyconnected to the conductive pattern 47 b formed on the printed circuitboard 40. The conductive pattern 47 b is connected to an output terminalof the signal transmission control circuit 41. It is to be noted that,in the present embodiment, the position indicator 1 acts as a positionindicator of the passive type which does not transmit a stylus positionsignal, and in this case, the center electrode 7 plays a role forsucking up charge from a conductor of the position detection system 2via a capacitive coupling portion.

The peripheral electrode 6 is provided around the center electrode 7.The combination of the peripheral electrode 6 and the center electrode 7is for a position indicator of the improved type of the passive typedescribed hereinabove. In the present embodiment, a shield member 8 foreffectively preventing electric interference between the peripheralelectrode 6 and the center electrode 7 is provided between theperipheral electrode 6 and the center electrode 7. The shield member 8in the present embodiment is provided so as to surround the centerelectrode 7. Consequently, the shield member 8 is interposed between theperipheral electrode 6 and the center electrode 7 to minimize thecoupling capacitance between the peripheral electrode 6 and the centerelectrode 7.

It is to be noted that also the center electrode 7 and the peripheralelectrode 6 configure a communication circuit (second communicationcircuit), and although it is described in the foregoing description thatthe center electrode 7 configures a transmission circuit (secondtransmission circuit) and the peripheral electrode 6 configures areception circuit (second reception circuit), the peripheral electrode 6and the center electrode 7 may otherwise be configured such that thecenter electrode 7 configures a reception circuit (second receptioncircuit) and the peripheral electrode 6 configures a transmissioncircuit (second transmission circuit).

The center electrode 7 as a core member is fitted, at an end portionthereof on the opposite side to the side on which it projects to theoutside, with the pen pressure detection circuit 9 disposed in thehollow portion of the housing 3 such that it is locked in the hollowportion of the housing 3 of the position indicator 1. It is to be notedthat, as hereinafter described, the center electrode 7 is configuredsuch that, if it is pulled out, then it is brought out of fitting withthe pen pressure detection circuit 9. In other words, the centerelectrode 7 as a core member can be replaced from the position indicator1.

The pen pressure detection circuit 9 is configured, in the presentexample, as a variable capacitor which demonstrates a capacitancecorresponding to a pressure (pen pressure) applied to the centerelectrode 7 as a core member (refer to, for example, Japanese PatentLaid-Open No. 2011-186803). The electrodes at the opposite ends of thevariable capacitor configuring the pen pressure detection circuit 9 areconnected, in FIG. 2A, to the signal transmission control circuit 41 bythe conductive pattern 47 c.

The signal transmission control circuit 41 performs determinationcontrol in regard to which one of a plurality of configuration types(modes) is to be applied to the position indicator 1 of the presentembodiment on the basis of information received from the outside via thewireless communication circuit 42 or information received via theperipheral electrode 6. Further, the signal transmission control circuit41 performs transmission control of a stylus position signal through thecenter electrode 7 on the basis of the determination control.Furthermore, the signal transmission control circuit 41 performstransmission control of additional information through the centerelectrode 7 or the wireless communication circuit 42.

Initial Setting of Position Indicator 1 of Embodiment andSynchronization Based on Signal from Position Detection System

In the present embodiment, as the position detection system 2 to be usedwith the position indicator 1, those of a plurality of configurationtypes such as the passive type, the improved type of the passive typeand the active type are available as described hereinabove. In thepresent embodiment, where the position detection system 2 includes awireless communication circuit capable of communicating with thewireless communication circuit 42 of the position indicator 1, pen typeinformation indicative of a configuration type with which the positiondetection system 2 can act is transmitted to the position indicator 1 bythe wireless communication circuit. The position indicator 1 receivesthe pen type information from the position detection system using thereception function of the wireless communication circuit 42 (example ofa reception function of the communication circuit), determines, on thebasis of the received pen type information, to which one of theconfiguration types (modes) the position indicator is to be set, andinitially sets so that the position indicator 1 has a configuration of aposition indicator of the determined configuration type.

In the case of a position indicator of the configuration type of thepassive type or the improved type of the passive type in which atransmission signal from the position detection system 2 side isreceived, the position indicator 1 determines to which one of theconfiguration types the position indicator is to be set by receiving asignal from the position detection system through the peripheralelectrode 6 (example of the reception function of the communicationcircuit), whereafter an initial setting is performed so that theposition indicator has a configuration of the determined type.

In this case, the passive type and the improved type of the passive typehave a difference in frequency of a signal from the position detectionsystem and a difference in signal contents (difference in spread code,difference in modulation method and so forth). Therefore, the positionindicator 1 decides the differences and determines which configurationtype the position indicator is to have from a result of the decision. Inthis case, also when information indicating a configuration type cannotbe acquired from the position detection system via the wirelesscommunication circuit 42, it can be decided which configuration type(mode) the position indicator is to have.

The signal transmission control circuit 41 of the position indicator 1performs an initial setting based on a determination process of theconfiguration type (mode) of the position indicator 1 on the basis ofinformation received from the position detection system 2 via thewireless communication circuit 42 or a signal received via theperipheral electrode 6 as described hereinabove. The signal transmissioncontrol circuit 41 performs a process for controlling the positionindicator 1 to perform, in the initially set configuration type (mode),transmission of a stylus position signal and additional informationsynchronized with a signal received from the position detection systemvia the wireless communication circuit 42 or the peripheral electrode 6.

Now, a process for the initial setting and the synchronization describedabove in a case in which the position indicator 1 performs an initialsetting on the basis of information received from the position detectionsystem 2 via the wireless communication circuit 42 and transmits astylus position signal and additional information to the positiondetection system 2 by the synchronization based on a signal receivedfrom the position detection system 2 via the wireless communicationcircuit 42 is described with reference to a timing chart of FIG. 3 .

In the present example, the position indicator 1 transmits a signal Spfor pairing with the position detection system 2 for communicationconnection intermittently in a fixed period To to the position detectionsystem 2 via the wireless communication circuit 42 as depicted in row Aof FIG. 3 until after so-called pairing between the position indicator 1and the position detection system 2, which is a state in which theposition indicator 1 is connected for communication to the positiondetection system 2 via the wireless communication circuit 42, iscompleted.

After the position detection system 2 confirms reception of the signalSp for pairing from the position indicator 1, it determines that pairingthereof with the position indicator 1 is possible and sends, in thepresent example, information indicating a configuration type of theposition indicator which is to act together with the position detectionsystem to the position indicator 1.

If the position indicator 1 confirms reception of the informationindicating a configuration type from the position detection system viathe wireless communication circuit 42 (refer to row A of FIG. 3 ), thenit determines that pairing with the position detection system 2 ispossible and performs an initial setting using the received informationindicating the configuration type. In particular, in the presentexample, the information indicating a configuration type is an exampleof information for the initial setting in the position indicator 1.

This initial setting includes, for example, setting of a frequency of asignal to be sent from the position indicator 1, selection of a signalto be sent from the position indicator 1 (selection of a stylus positionsignal and additional information), and a transmission timing of asignal to be sent from the position indicator 1 (for example, in thecase of transmission of one piece of data for each externalsynchronizing signal, in the case where no external synchronizing signalis available and transmission is repeated at designated intervals or ina like case).

In particular, the position indicator 1, on the basis of the informationindicating a configuration type as an example of setting informationfrom the position detection system 2, determines a frequency of atransmission signal to be transmitted from the pen tip, determines aperiod of a continuous signal to be transmitted from the pen tip,determines from which one of the pen tip and the wireless communicationcircuit 42 pen pressure information, side switch information andidentification information ID are to be transmitted, and so forth andperforms an initial setting process in accordance with thedeterminations to perform an initial setting.

It is to be noted that, in the foregoing description, the signal Sp forpairing is transmitted from the position indicator 1, and when thesignal Sp is received by the position detection system 2, the positiondetection system 2 sends information indicating a configuration type tothe position indicator 1 and then the position indicator 1 performs theinitial setting process on the basis of the information indicating theconfiguration type. However, the position detection system 2 maytransmit a signal Sp for pairing intermittently in a fixed period To tothe position indicator 1 via the wireless communication circuit. In thiscase, the signal Sp for pairing includes information indicating aconfiguration type of the position indicator which is to act togetherwith the position detection system 2.

In this case, when the position indicator 1 receives the signal Sp fromthe position detection system via the wireless communication circuit 42,it performs the initial setting process using the information indicatingthe configuration type included in the signal Sp. Then, after theinitial setting process is completed, the position indicator 1 transmitsa response signifying that the signal Sp for pairing is received andpairing is completed to the position detection system 2.

If pairing is performed in such a manner as described above and theinitial setting process in the position indicator 1 is completed, thenthe position indicator 1 prepares to start transmission of a stylusposition signal and additional information to the position detectionsystem in accordance with the initial setting process. Further, if theposition detection system 2 recognizes that pairing with the positionindicator 1 is possible, then it stops the transmission of the signal Spvia the wireless communication circuit and instead sends a referencesignal (external synchronizing signal) for a transmission timing of asignal from the position indicator 1 to the position indicator 1 via thewireless communication circuit.

The transmission of a stylus position signal and additional informationfrom the position indicator 1 to the position detection system 2 isperformed in synchronism with a signal (external synchronizing signal)from the position detection system received by the wirelesscommunication circuit 42. Consequently, in the position detectionsystem, a signal from the position indicator 1 can be received withcertainty and accuracy.

Example of Establishment of Synchronism

Several examples of how to establish synchronism between the positionindicator 1 and the position detection system 2 after pairing betweenthe position indicator 1 and the position detection system 2 isestablished are described with reference to rows B, C, and D of FIG. 3 .It is to be noted that the examples of rows B and C of FIG. 3 aredirected to a case in which the position indicator 1 transmits all of astylus position signal and additional information to the positiondetection system 2 via the center electrode 7 (or the peripheralelectrode 6), and the example of row D of FIG. 3 is directed to anothercase in which a stylus position signal and pen pressure informationwithin additional information are sent to the position detection system2 via the center electrode 7 (or the peripheral electrode 6) whileidentification information ID is sent to the position detection system 2via the wireless communication circuit 42.

First Example

In the first example, the position detection system 2 transmits, afterpairing with the position indicator 1, an external synchronizing signalSYC, for example, in a predetermined period via the wirelesscommunication circuit. When the position indicator 1 receives theexternal synchronizing signal SYC as depicted in row B of FIG. 3 , ittransmits, on the basis of the reception, a stylus position signal(burst signal) and additional information to the position detectionsystem 2 via the center electrode 7 (or the peripheral electrode 6).

It is to be noted that, also in this first example, all of additionalinformation may not be transmitted to the position detection system 2via the center electrode 7 (or the peripheral electrode 6) but part ofthe additional information such as identification information ID or allof the additional information may be transmitted to the positiondetection system 2 via the wireless communication circuit 42 at a timingbased on the external synchronizing signal SYC.

After the external synchronizing signal SYC is sent, the positiondetection system 2 may receive a stylus position signal and additionalinformation sent thereto from the position indicator 1 at a timingsynchronized with the external synchronizing signal, and therefore, theposition detection system 2 can acquire a signal from the positionindicator 1 with accuracy. It is to be noted that additional informationmay not always be sent together with a stylus position signal but may besent at predetermined intervals.

Second Example

In the present second example, the position indicator 1 transmits astylus position signal (burst signal) and additional information to theposition detection system 2 via the center electrode 7 (or theperipheral electrode 6) on the basis of the external synchronizingsignal SYC from the position detection system 2 similarly as in thefirst example.

However, in the present second example, a timing signal generationcircuit for generating a signal synchronized with the externalsynchronizing signal SYC from the position detection system 2 isprovided. Therefore, the position detection system 2 need not transmitthe external synchronizing signal SYC at every timing at which theposition indicator 1 is to transmit a stylus position signal andadditional information but can transmit the external synchronizingsignal SYC at predetermined time intervals as depicted in row C of FIG.3 .

In the present second example, the oscillator of the position detectionsystem and the oscillator of the timing signal generation circuit of theposition indicator 1 operate with frequencies substantially equal toeach other. However, the difference in frequency gradually displacestimings of them as time passes. The transmission interval of theexternal synchronizing signal SYC from the position detection system 2is set so as to be equal to or smaller than an interval within which thetiming displacement falls within a displacement which does not have aninfluence on the action.

Third Example

The first example and the second example described above are directed toan example wherein the reception timing of the external synchronizingsignal SYC and the transmission timing of a stylus position signal andadditional information do not overlap with each other in the positionindicator 1. However, if the position indicator 1 is configured suchthat it includes a timing signal generation circuit for generating asignal synchronized with the external synchronizing signal SYC from theposition detection system 2 similarly as in the second example, then thereception timing of the external synchronizing signal SYC and thetransmission timing of a stylus position signal and additionalinformation may overlap with each other. The third example is an examplein this case.

In particular, in the present third example, the position indicator 1includes a timing signal generation circuit for generating a signalsynchronized with the external synchronizing signal SYC from theposition detection system 2 as depicted in row D of FIG. 3 . Then, thesignal from this timing signal generation circuit is used to set atransmission timing of a stylus position signal and additionalinformation in a next cycle to a timing synchronized with the externalsynchronizing signal SYC.

With the present third example, it is possible to raise the transferrate of a stylus position signal and additional information. It is to benoted that, also in the present third example, the position detectionsystem 2 need not transmit the external synchronizing signal SYC inaccordance with a transmission timing of a stylus position signal andadditional information from the position indicator 1 but may transmitthe external synchronizing signal SYC after time intervals.

It is to be noted that, in the first to third examples described above,the position indicator 1 receives an external synchronizing signal SYCfrom the position detection system 2 and transmits a stylus positionsignal and additional information at a timing synchronized with thereceived external synchronizing signal SYC. However, a synchronizingsignal for conveying a timing at which a stylus position signal andadditional information are to be transmitted may be transmitted from theposition indicator 1 to the position detection system 2 such that theposition detection system 2 receives a signal transmitted thereto fromthe position indicator 1 on the basis of the synchronizing signal fromthe position indicator 1.

It is to be noted that, in addition to the example described above,there may be a case in which synchronization based on a synchronizingsignal using a wireless communication circuit is not performed betweenthe position indicator 1 and the position detection system 2. Action inthis case is described.

1. In a case where, although the position detection system 2 has awireless communication circuit and transmits setting information for theinitial setting in the position indicator 1 (for example, informationindicating a configuration type), no synchronization is performed.

In this case, although pairing between the position indicator 1 and theposition detection system 2 is established and exchange of informationfor the initial setting is performed using the wireless communicationcircuit, since no synchronization is performed, signal transmission fromthe position indicator 1 is started on the basis of initial settinginformation.

2. In another case where the position detection system 2 does not have awireless communication circuit and setting information is transmittedfrom a sensor to the position indicator 1.

In this case, the reception circuit configured from the center electrode7 or the peripheral electrode 6 on the pen tip side of the positionindicator 1 receives a signal from the sensor of the position detectionsystem 2 and performs the initial setting and then starts communicationwith the position detection system 2.

3. In a further case where the position detection system 2 does not havea wireless communication circuit and setting information is nottransmitted from the sensor.

In this case, the position indicator 1 and the position detection system2 cannot perform pairing, and the position indicator 1 begins totransmit a signal on the basis of a default value set (stored) inadvance in the position indicator 1.

Description of Example of Configuration of Internal Electronic Circuitof Position Indicator 1 of Embodiment

FIG. 4 is a block diagram depicting a configuration of an electroniccircuit formed on the printed circuit board 40 in the housing 3 of theposition indicator 1 of the present embodiment and is a view principallydepicting an example of a detailed internal configuration of the signaltransmission control circuit 41.

As depicted in FIG. 4 , the signal transmission control circuit 41 isconfigured including a control circuit 410 configured, for example, froman IC (Integrated Circuit) or microprocessor, a pen type decisioncircuit 411, a center electrode transmission signal generation circuit412, a wireless transmission signal generation circuit 413, a switchcircuit 414 for stylus position signal selection, a feedback signalgeneration circuit 415, a position indicator of the passive type, andswitch circuits 416 and 417 for switching between position indicators ofthe improved type of the passive type and the active type.

The control circuit 410 includes, as circuits thereof, a configurationsetting circuit 4101 for performing the initial setting processdescribed hereinabove, and a synchronization circuit 4102 for causing atransmission signal to be transmitted in synchronism with the externalsynchronizing signal SYC from the position detection system 2.

The variable capacitor configured from the pen pressure detectioncircuit 9 is connected to the control circuit 410, and the controlcircuit 410 calculates a pressure (pen pressure value) applied to thecenter electrode 7 from the capacitance of the variable capacitorconfigured from the pen pressure detection circuit 9. Further, an on-offstatus signal of the side switch 43 is supplied to the control circuit410. The control circuit 410 generates side switch information which isadditional information relating to the side switch 43 from the on-offstatus signal of the side switch 43. Further, the ID memory 44 isconnected to the control circuit 410, and the control circuit 410 readsout and acquires identification information (ID) of the positionindicator 1 from the ID memory 44 as occasion demands. It is to be notedthat the ID memory 44 which stores identification information in advancemay be accommodated in the position indicator 1 or may be configuredsuch that identification information which is stored contents of the IDmemory 44 is rewritten, for example, in accordance with a command fromthe position detection system 2 received via the wireless communicationcircuit 42.

The configuration setting circuit 4101 of the control circuit 410performs an initial setting process regarding whether a plurality oftypes of additional information, in the present example, pen pressureinformation, side switch information and identification information, areto be sent from the center electrode 7 or to be sent by wirelesstransmission from the wireless communication circuit 42 in response toinformation based on a result of the pen type decision from the pen typedecision circuit 411.

The control circuit 410 supplies, on the basis of the initial settingprocess, additional information to be sent via the center electrode 7 tothe center electrode transmission signal generation circuit 412 andsupplies additional information to be sent via the wirelesscommunication circuit 42 to the wireless transmission signal generationcircuit 413.

The center electrode transmission signal generation circuit 412 isconnected to the center electrode 7 and transmits additional informationto be sent to the position detection system 2 via the center electrode 7together with a stylus position signal as hereinafter described. Thewireless transmission signal generation circuit 413 is connected to atransmission circuit 421 of the wireless communication circuit 42, andadditional information to be sent is transmitted by wirelesstransmission to the position detection system 2 via the transmissioncircuit 421. In this case, the control circuit 410 receives the externalsynchronizing signal SYC from the position detection system 2 via areception circuit 422 of the wireless communication circuit 42 andcontrols, by the synchronization circuit 4102, based on the receivedexternal synchronizing signal SYC such that a stylus position signal andadditional information are transmitted from the center electrodetransmission signal generation circuit 412 via the center electrode 7 oradditional information is transmitted from the wireless transmissionsignal generation circuit 413 via the transmission circuit 421 of thewireless communication circuit 42.

To the center electrode transmission signal generation circuit 412, analternating signal of the frequency f1 from the oscillator 45 or analternating signal of the frequency f2 from the oscillator 46 issupplied as a signal for generating a stylus position signal to be sentin response to switching selection of the switch circuit 414 by thecontrol circuit 410 and a feedback signal from the feedback signalgeneration circuit 415 is supplied as a stylus position signal to besent. The feedback signal generation circuit 415 performs signalenhancement of a signal received from the position detection system 2via the peripheral electrode 6 by amplification and further performsphase inversion in the present example. An example of a configurationand a process of the feedback signal generation circuit 415 ishereinafter described in detail. The control circuit 410 generates aswitching selection signal for the switch circuit 414 on the basis ofinitial setting information set on the basis of a result of a pen typedecision from the pen type decision circuit 411.

A connection portion of the center electrode transmission signalgeneration circuit 412 to the center electrode 7 is connected to theconductor portion 32 of the housing 3 via the switch circuit 416.Meanwhile, the peripheral electrode 6 is connected to the conductorportion 32 of the housing 3 via the switch circuit 417. The switchcircuits 416 and 417 are switched in accordance with an on/offcontrolling signal from the control circuit 410. The control circuit 410generates on/off controlling signals for the switch circuits 416 and 417on the basis of initial setting information set on the basis of a resultof the pen type decision from the pen type decision circuit 411.

The pen type decision circuit 411 is configured from a pen type tablememory 4111 and a decision processing circuit 4112. To the decisionprocessing circuit 4112 of the pen type decision circuit 411,information from the position detection system 2 received by thereception circuit 422 of the wireless communication circuit 42 issupplied and a signal received from the position detection system 2 viathe peripheral electrode 6 is supplied.

In the pen type table memory 4111, a plurality of differentconfiguration types for the position indicator 1 and, for the positionindicator of each of the configuration types, whether a stylus positionsignal is to be sent and a frequency of an oscillator for generating astylus position signal to be sent as well as pen type table informationregarding whether additional information is to be sent from the centerelectrode 7 or via the wireless communication circuit 42 are stored.Although this pen type table information may be stored in advance in thepen type table memory 4111, it is configured in the present example suchthat writing into and rewriting of the pen type table information can beperformed by a command from the position detection system 2 via thewireless communication circuit 42.

The decision processing circuit 4112 discriminates information from theposition detection system 2 received by the reception circuit 422 of thewireless communication circuit 42 or a signal received from the sensorcircuit of the position detection system 2 via the peripheral electrode6 and refers to the pen type table information of the pen type tablememory 4111 to discriminate a configuration type for a positionindicator compatible with the position detection system 2 to be usedtogether with the position indicator 1. Then, the decision processingcircuit 4112 generates information regarding whether or not there is asignal to be sent from the center electrode 7, information regardingwhat are a stylus position signal and additional information to be sentfrom the center electrode 7 and information regarding what is additionalinformation to be transmitted via the wireless communication circuit 42and supplies the generated information to the control circuit 410.

The control circuit 410 generates a switch selection signal for theswitch circuit 414 and on-off controlling signals for the switchcircuits 416 and 417 on the basis of the initial setting set on thebasis of information from the pen type decision circuit 411 and suppliesthe generated signals to the switch circuits 414, 416 and 417. Further,the control circuit 410 determines additional information to be suppliedto the center electrode transmission signal generation circuit 412 andadditional information to be supplied to the wireless transmissionsignal generation circuit 413 and supplies the determined additionalinformation to them, respectively.

FIG. 5 depicts an example of the pen type table information in the pentype decision circuit 411. The example of FIG. 5 is table informationregarding five different types of position indicators, including aconfiguration type 1 to a configuration type 5 (mode 1 to mode 5). Afterthe configuration type (mode) for a position indicator is determined,the pen type decision circuit 411 refers to the pen type tableinformation to generate control information to be supplied to thecontrol circuit 410. In the following, that the configuration types(modes) are configured by switching control by the control circuit 410in the position indicator 1 of the present embodiment is described.

The configuration type 1 (mode 1) is a position indicator of the passivetype, and in the configuration type 1 (mode 1), no signal is transmittedfrom the center electrode 7 while all additional information istransmitted via the wireless communication circuit 42. In particular, inthe signal transmission control circuit 41 of the position indicator 1,if the pen type decision circuit 411 decides the configuration type 1(mode 1), then the control circuit 410 switches on the switch circuits416 and 417, and places the center electrode transmission signalgeneration circuit 412 into an inactive state. The switch circuit 417may be off. Then, the control circuit 410 causes the transmissioncircuit 421 of the wireless communication circuit 42 to transmit alladditional information to the position detection system 2 via thewireless transmission signal generation circuit 413. It is to be notedthat identification information need not occasionally be transmitted asadditional information.

The configuration type 2 (mode 2) is a position indicator of theimproved type of the passive type. If the pen type decision circuit 411decides this configuration type 2 (mode 2), then the control circuit 410switches off the switch circuits 416 and 417 on the basis of theinformation from the pen type decision circuit 411 and switches theswitch circuit 414 to a state in which it selects a signal from thefeedback signal generation circuit 415. Then, additional information iscontrolled by the control circuit 410 so that all of it is transmittedfrom the transmission circuit 421 of the wireless communication circuit42 to the position detection system 2 via the wireless transmissionsignal generation circuit 413. It is to be noted that identificationinformation need not occasionally be transmitted as additionalinformation.

The configuration type 3 (mode 3) is a first type of a positionindicator of the active type. If the pen type decision circuit 411decides this configuration type 3 (mode 3), then the control circuit 410switches off the switch circuit 416 and switches on the switch circuit417 on the basis of the information from the pen type decision circuit411 and switches the switch circuit 414, in the present example, to astate in which it selects an alternating signal from the oscillator 45of the frequency f1. Then, the control circuit 410 causes thetransmission circuit 421 of the wireless communication circuit 42 totransmit all additional information to the position detection system 2via the wireless transmission signal generation circuit 413. It is to benoted that identification information need not occasionally betransmitted as additional information.

The configuration type 4 (mode 4) is a second type of a positionindicator of the active type. If the pen type decision circuit 411decides the configuration type 4 (mode 4), then the control circuit 410switches off the switch circuit 416 and switches on the switch circuit417 on the basis of the information from the pen type decision circuit411 and switches the switch circuit 414, in the present example, to astate in which it selects an alternating signal from the oscillator 46of the frequency f2. Then, pen pressure information and side switchinformation from within additional information are sent from the centerelectrode 7 together with a stylus position signal while identificationinformation ID is controlled so as to be transmitted from thetransmission circuit 421 of the wireless communication circuit 42 to theposition detection system 2 via the wireless transmission signalgeneration circuit 413.

The configuration type 5 (mode 5) is a third type of a positionindicator of the active type. If the pen type decision circuit 411decides this configuration type 5 (mode 5), then the control circuit 410switches off the switch circuit 416 and switches on the switch circuit417 on the basis of the information from the pen type decision circuit411 and switches the switch circuit 414, in the present example, to astate in which it selects an alternating signal from the oscillator 46of the frequency f2. Then, all additional information is controlled soas to be transmitted from the center electrode 7 together with a stylusposition signal.

The signal transmission control circuit 41 decides a configuration typeof a position indicator on the basis of information and a signalreceived from the reception circuit 422 of the wireless communicationcircuit 42 and the sensor circuit of the position detection system 2 viathe peripheral electrode 6 and controls the position indicator 1 so asto have a configuration of a position indicator of the decidedconfiguration type in such a manner as described above.

Accordingly, the position indicator 1 of the present embodiment canautomatically configure itself according to various configuration typescompatible with position detection systems 2 of various types. In otherwords, only the position indicator 1 of the present embodiment is neededto input a position indication to a plurality of position detectionsystems 2 of various types. Therefore, there is no necessity to preparedifferent position indicators for individual ones of a plurality ofposition detection systems 2 of various types, which is very convenient,and to the user, also the burden in regard to the cost is reduced.

It is to be noted that the pen type information from the positiondetection system 2 received via the wireless communication circuit 42 isnot limited to information of configuration types for directlyidentifying the configuration types 1 to 5, but may be numbers of theconfiguration types 1 to 5 in the pen type table information orinformation indirectly indicating addresses of the configuration typesin the pen type table memory 4111, for example.

It is to be noted that, in FIG. 4 , the processing functions of thedecision processing circuit 4112 of the pen type decision circuit 411,the center electrode transmission signal generation circuit 412 and thewireless transmission signal generation circuit 413 can be configuredalso as software executed by the control circuit 410. This similarlyapplies also to the feedback signal generation circuit 415.

Example of Processing Action of Signal Transmission Control Circuit 41

Now, an example of processing actions performed by the signaltransmission control circuit 41 after the power supply switch 48 isswitched on is described with reference to the flow charts of FIGS. 6and 7 .

The signal transmission control circuit 41 first decides whether or notinformation is received by the reception circuit 422 of the wirelesscommunication circuit 42 (S1) and decides, if it decides thatinformation is received, whether or not the received information is pentype information (S2). If it is decided at S2 that the receivedinformation is pen type information, then the signal transmissioncontrol circuit 41 decides a configuration type (pen type) of a positionindicator on the basis of the received pen type information and refersto the pen type table memory 4111 to determine signals to be transmittedfrom the center electrode 7 and the transmission circuit 421 of thewireless communication circuit 42, and performs an initial settingprocess (S3). This initial setting process includes also settingregarding whether or not a stylus position signal is to be transmittedfrom the center electrode 7 described hereinabove.

Next, after S3, the signal transmission control circuit 41 performssignal transmission based on the initial setting process in accordancewith the configuration type decided at S3 via the center electrode 7 andthe transmission circuit 421 of the wireless communication circuit 42(S4).

Then, the signal transmission control circuit 41 decides whether or notit is impossible to receive information from the position detectionsystem 2 via the reception circuit 422 of the wireless communicationcircuit 42 (S5) and returns, if it is decided that it is not impossibleto receive information, the processing to S4 to continue the signaltransmission in accordance with the decided configuration type.

If it is decided at S5 that it is impossible to receive information fromthe position detection system 2 via the reception circuit 422 of thewireless communication circuit 42, then the signal transmission controlcircuit 41 decides whether or not a predetermined period of time or morehas elapsed after it became impossible to receive information (S6). Ifit is decided at S6 that the predetermined period of time or more hasnot elapsed, then the signal transmission control circuit 41 returns theprocessing to S4 to continue the signal transmission in accordance withthe decided configuration type.

If it is decided at S6 that the predetermined period of time or more haselapsed, then the signal transmission control circuit 41 stops thesignal transmission from the center electrode 7 and the transmissioncircuit 421 of the wireless communication circuit 42 and places theposition indicator 1 into a sleep state (S7). In this sleep state, inorder to reduce the dissipation of the battery 5 as far as possible toachieve power saving, while supply of power to the reception circuit 422of the wireless communication circuit 42 and the control circuit 410 andthe pen type decision circuit 411 of the signal transmission controlcircuit 41 is maintained, useless voltage supply to the other circuitsis stopped.

Then, subsequently to S7, the signal transmission control circuit 41returns the processing to step S1 to repeat the processes at the stepsbeginning with step S1 described above.

If it is decided at S1 that information is not received by the receptioncircuit 422 of the wireless communication circuit 42 or if it is decidedat S2 that the received information is not pen type information, thenthe signal transmission control circuit 41 decides whether or not asignal is received via the peripheral electrode 6 (S11 of FIG. 7 ). Ifit is decided at S11 that a signal is not received via the peripheralelectrode 6, then the signal transmission control circuit 41 switches onthe switch circuit 416 to connect the center electrode 7 to thegrounding conductor (ground) of the printed circuit board 40 via theconductor portion 32 to establish a state of the configuration type 1(S18). Then, after S18, the signal transmission control circuit 41returns the processing to S1 of FIG. 6 to repeat the processes beginningwith S1.

Then, if it is decided at S11 that a signal is received via theperipheral electrode 6, then it is decided whether or not decision of apen type from the reception signal is possible (S12). If it is decidedat S12 that decision of a pen type is not possible, then the signaltransmission control circuit 41 switches on the switch circuit 416 toconnect the center electrode 7 to the grounding conductor (ground) ofthe printed circuit board 40 via the conductor portion 32 to establish astate of the configuration type 1 (S18). Then, after S18, the signaltransmission control circuit 41 returns the processing to S1 of FIG. 6to repeat the processes beginning with S1.

If it is decided at S12 that decision of a pen type is possible, thenthe signal transmission control circuit 41 decides a configuration type(pen type) of the position indicator on the basis of the received signaland refers to the pen type table memory 4111 to determine signals to betransmitted from the center electrode 7 and the transmission circuit 421of the wireless communication circuit 42, and performs an initialsetting process (S13). This initial setting process includes settingalso of whether or not a stylus position signal is to be transmittedfrom the center electrode 7 as described hereinabove.

Next, after S13, the signal transmission control circuit 41 executessignal transmission based on the initial setting process in accordancewith the configuration type decided at S13 via the center electrode 7and the transmission circuit 421 of the wireless communication circuit42 (S14).

Then, the signal transmission control circuit 41 decides whether or notit is impossible to receive a signal via the peripheral electrode 6(S15), and returns, when it is decided that it is not impossible toreceive a signal, the processing to S14 to continue the signaltransmission in accordance with the decided configuration type.

If it is decided at S15 that it is impossible to receive a signal viathe peripheral electrode 6, then the signal transmission control circuit41 decides whether or not a predetermined period of time or more haselapsed after it became impossible to receive a signal (S16). If it isdecided at S16 that the predetermined period of time or more has notelapsed, then the signal transmission control circuit 41 returns theprocessing to S14 to continue the signal transmission in accordance withthe decided configuration type.

If it is decided at step that the predetermine time period or more haselapsed, then the signal transmission control circuit 41 stops thesignal transmission from the center electrode 7 and the transmissioncircuit 421 of the wireless communication circuit 42 and places theposition indicator 1 into a sleep state (S17). Then, after S17, thesignal transmission control circuit 41 returns the processing to S1 torepeat the processes beginning with S1 described hereinabove.

Description of Action of Position Indicator of Configuration Type andCorresponding Position Detection System Position Indicator 1A ofConfiguration Type 2 and Corresponding Position Detection System 2A

FIG. 8 is a view depicting an example of a circuit of major part of aposition indicator 1A of the configuration type 2 and particularlydepicts an example of a circuit configuration of a feedback signalgeneration circuit 415 and an example of a circuit configuration of apower supply circuit 50 whose description is omitted in the foregoingdescription.

The power supply circuit 50 includes a DC/DC converter 501, whichgenerates a power supply voltage +Vcc from the voltage of the battery 5and supplies the power supply voltage +Vcc to the signal transmissioncontrol circuit 41 and other circuits.

In the power supply circuit 50, the power supply switch 48 is providedbetween the DC/DC converter 501 and the battery 5. Further, a seriescircuit of a resistor 502 and the LED 49 is connected between an outputterminal of the DC/DC converter 501 and the grounding conductor.Furthermore, the output terminal of the DC/DC converter 501 is connectedto the grounding conductor via a series connection of a resistor 503 andanother resistor 504, and a reference voltage Vref (=Vcc/2) is outputtedfrom a connection point of the resistor 503 and the resistor 504.

The feedback signal generation circuit 415 is configured, in the presentexample, as a signal enhancement processing circuit and is configuredfrom a sense amplifier 510, a signal amplification factor variationcircuit 520 and a transformer 530.

In the present example, the sense amplifier 510 is configured from anoperational amplifier 511, and a capacitor 512 connected between aninverting input terminal and an output terminal of the operationalamplifier 511. The inverting input terminal of the operational amplifier511 is connected to a connection terminal 513 connected to theperipheral electrode 6. Meanwhile, to a non-inverting input terminal ofthe operational amplifier 511, the reference voltage Vref describedhereinabove is supplied.

When the position indicator 1A is disposed on a position detectionsystem 2A, the peripheral electrode 6 of the position indicator 1A andthe position detection system 2A are coupled to each other via acapacitance C1 as depicted in FIG. 1 . Since an alternating signal flowsto the position detection system 2A as hereinafter described, thisalternating signal is supplied as a current signal to the connectionterminal 513 via the capacitance C1 and the peripheral electrode 6 andis inputted to the sense amplifier 510. The capacitor 512 is providedfor detecting the current signal inputted via the capacitance C1.

Then, the sense amplifier 510 phase-inverts the alternating signalinputted as a current signal via the connection terminal 513 and outputsthe resulting alternating signal to the signal amplification factorvariation circuit 520.

The signal amplification factor variation circuit 520 is configured froman operational amplifier 521, and a variable resistor 522 connectedbetween an inverting input terminal and an output terminal of theoperational amplifier 521. By variably setting the resistance value ofthe variable resistor 522, an amplification factor of the operationalamplifier 521 is variably set, and as a result, a signal detectionsensitivity of the position indicator 1A is controlled.

The alternating signal amplified by the signal amplification factorvariation circuit 520 is supplied to a primary winding 530 a of thetransformer 530. The ratio between a number n1 of turns of the primarywinding 530 a and a number n2 of turns of a secondary winding 530 b ofthe transformer 530 is set such that the number of turns of thesecondary winding 530 b is higher (n1<n2), for example, like n1:n2=1:10.Accordingly, on the secondary winding 530 b side of the transformer 530,an alternating signal (voltage signal) of an increased amplitude isobtained by multiplication of the amplitude of an output signal of thesignal amplification factor variation circuit 520 in accordance with thewinding ratio.

The secondary winding 530 b of the transformer 530 is connected at oneterminal thereof to a connection terminal 523 connected to a core member71 formed from a bar-like conductor of the center electrode 7 shieldedby the shield member 8. The secondary winding 530 b of the transformer530 is connected at the other terminal thereof to the groundingconductor of the printed circuit board 40. Accordingly, an output signalformed as an alternating signal voltage of an increased amplitude by thefeedback signal generation circuit 415 is supplied to the centerelectrode 7 via the connection terminal 523.

When the position indicator 1A is disposed on the position detectionsystem 2A, since the center electrode 7 of the position indicator 1A andthe position detection system 2A are coupled to each other via acapacitance, the alternating signal is fed back from the positionindicator 1A to the position detection system 2A via the centerelectrode 7 of the position indicator 1A.

Now, the position detection system 2A of the present example isdescribed with reference to FIG. 9 . The position detection system 2A ofthe present example has a configuration of a position detection systemof a mutual capacitance type wherein a sensor electrode is configuredfrom an input electrode and an output electrode and a variation of acoupling capacitance at a touch point at which the position indicator 1Acontacts with the position detection system 2A is detected.

As depicted in FIG. 9 , the position detection system 2A of the presentexample includes a sensor 20A, a transmission circuit 21, a receptioncircuit 22, a wireless communication circuit 25 and a control circuit220A. The sensor circuit 20A includes a plurality of, in the presentexample, m, linear transmission conductors 23Y₁, 23Y₂, . . . , and23Y_(m) (m is an integer equal to or greater than 1) extending in ahorizontal direction (X axis direction) of the sensor input face, and aplurality of, in the present example, n, reception conductors 24X₁,24X₂, . . . , and 24X_(n) (n is an integer equal to or greater than 1)extending in a vertical direction (Y axis direction) of the sensor inputface orthogonal to the transmission conductors 23Y₁ to 23Y_(m). Theplurality of transmission conductors 23Y₁ to 23Y_(m) are disposed atequal distances in the Y axis direction and connected to thetransmission circuit 21. Meanwhile, the plurality of receptionconductors 24X₁ to 24X_(n) are disposed at equal distances in the X axisdirection and are connected to the reception circuit 22.

It is to be noted that, in the following description of the presentspecification, when there is no necessity to individually distinguishthe transmission conductors 23Y₁ to 23Y_(m) and the reception conductors24X₁ to 24X_(n), each of them is referred to as transmission conductor23Y and reception conductor 24X.

The plurality of transmission conductors 23Y and the plurality ofreception conductors 24X are individually disposed in a spacedrelationship from each other and have a mutually orthogonal dispositionrelationship such that a plurality of intersecting points (cross points)are formed. At each cross point, it can be considered that atransmission conductor 23Y and a reception conductor 24X are coupled toeach other through a predetermined capacitance.

The transmission circuit 21 supplies a predetermined alternating signalto the transmission conductors 23Y under the control of the controlcircuit 220A. In this case, the transmission circuit 21 may supply asame alternating signal to the plurality of transmission conductors23Y₁, 23Y₂, . . . , and 23Y_(m) while they are successively switched oneby one or may supply a plurality of alternating signals different fromeach other simultaneously to the plurality of transmission conductors23Y₁, 23Y₂, . . . , and 23Y_(m). Alternatively, the plurality oftransmission conductors 23Y₁, 23Y₂, . . . , and 23Y_(m) may be dividedinto plurality of groups, for which alternating signals different fromone another are used.

The reception circuit 22 detects a signal component when an alternatingsignal supplied to a transmission conductor 23Y is transmitted to eachof the reception conductors 24X₁, 24X₂, . . . , and 24X_(n) via thepredetermined capacitance described above under the control of thecontrol circuit 220A. If it is assumed that the coupling capacitancebetween a transmission conductor 23Y and a reception conductor 24X isequal at all cross points, then when the position indicator 1A is notdisposed on the sensor circuit 20A, a reception signal of apredetermined level is detected from all of the reception conductors24X₁, 24X₂, . . . , and 24X_(n) of the sensor circuit 20A by thereception circuit 22.

In contrast, if the position indicator 1A contacts with the sensor 20A,then a transmission conductor 23Y and a reception conductor 24X whichconfigure a cross point at the contact position and the positionindicator 1A couple to each other via the capacitance. In other words,the capacitance is varied by the position indicator 1A, and thereception signal level obtained from the reception conductor 24X at thecross point at which the position indicator 1A is disposed varies incomparison with the reception signal level at the other cross points.

The reception circuit 22 detects a reception conductor 24X whichdemonstrates a variation of the level of the reception signal thereofamong the plurality of reception conductors 24X₁, 24X₂, . . . , and24X_(n) to detect the indicated position by the position indicator 1A.Another control circuit of the position detection system 2 not depicteddetects the cross point, at which the position indicator 1A contacts, bydetecting the transmission conductor 23Y to which an alternating signalis supplied from the transmission circuit 21 and the reception conductor24X at which the variation of the reception signal level is detected bythe reception circuit 22.

Also when not the position indicator 1A but a finger approaches orcontacts with the sensor 20A, the position detection system 2 detectsthe cross point approached or contacted by the finger in accordance witha similar principle. In this case, part of the alternating signalsupplied to the transmission conductor 23Y flows to the ground via thefinger and further via the body of the user. Therefore, the receptionsignal level of the reception conductor 24X which configures the crosspoint at which the finger is disposed varies. The reception circuit 22detects the variation of the reception signal level to detect thereception conductor 24X which configures the cross point at which thefinger is disposed.

In the case of a position indicator of the configuration type 1, theposition detection system 2A can perform detection of an indicatedposition on the sensor 20A in accordance with a principle similar tothat of position detection of a finger. However, in the case of aposition indicator of the configuration type 1, since the contact areaof the position indicator is not greater than that of the finger, thecoupling capacitance is low and the position detection system 2A is lowin detection sensitivity. Therefore, a position detection systemcompatible with a position indicator of the configuration type 1compensates for a drop of the detection sensitivity by using a spreadcode as an alternating signal to be transmitted to the positionindicator and taking the correlation between the transmission signal andthe reception signal to detect the indicated position by the positionindicator or the like.

In contrast, in the case of the position indicator 1A of theconfiguration type 2 and the position detection system 2A, even if aspread code or the like is not used, the affinity between the positionindicator 1A and the position detection system 2A is high and besidesthe general versatility is high. Further, a predetermined waveformcorrelativity is assured between the input signal and the output signal,and position detection by the sensor 20A becomes possible with a highsensitivity.

In particular, if the position indicator 1A is positioned closely to orcontacted with the sensor 20A of the position detection system 2A, thenthe alternating signal supplied to the transmission conductor 23Y isinputted as a current signal to the feedback signal generation circuit415 through the connection terminal 513 via the capacitance C1 andfurther via the peripheral electrode 6 as depicted in FIG. 1 .

The alternating signal (current signal) inputted to the feedback signalgeneration circuit 415 is phase-inverted by the sense amplifier 510 andthen amplified by the signal amplification factor variation circuit 520,whereafter it is boosted (multiplied) and signal-enhanced by thetransformer 530 and is supplied as a voltage signal to the centerelectrode 7 via the connection terminal 523. In particular, thealternating signal inputted from the sensor 20A to the feedback signalgeneration circuit 415 via the peripheral electrode 6 is inverted inphase and converted into a signal of a greater amplitude by the feedbacksignal generation circuit 415 and then fed back to the sensor 20A viathe center electrode 7.

In this case, since the alternating signal fed back from the centerelectrode 7 of the position indicator 1A to the sensor 20A of theposition detection system 2A is an enhanced signal in the reverse phaseof the alternating signal supplied to the transmission conductor 23Y,the position indicator 1A functions to increase the variation of thealternating signal of the reception signal of the reception conductor24X. Therefore, the position detection system 2A can detect the contactposition of the position indicator 1A with a high sensitivity. It is tobe noted that, if the grounding conductor of the position indicator 1Ais connected to the human body, then the detection action is stabilizedfurther. In particular, in the present embodiment, the housing 3 of theposition indicator 1A is covered with the conductor portion 32 connectedto the grounding conductor of the printed circuit board 40. Therefore,the alternating signal supplied to the transmission conductor 23Y in theposition detection system 2A flows to the ground via the positionindicator 1A and further via the human body of the user thereby toachieve further stabilization of the signal detection action.

Further, where the voltage at the transmission conductor 23Y of thesensor 20A of the position detection system 2A is represented by V, thevoltage of the center electrode 7 of the position indicator 1A of thepresent embodiment by e and the capacitance between the peripheralelectrode 6 and the center electrode 7 by C2 (refer to FIG. 1 ), thenthey have the following relationship:e≤C1/C2·VTherefore, in order to make the potential e at the center electrode 7higher, it is advantageous to minimize the capacitance C2 between theperipheral electrode 6 and the center electrode 7.

To this end, in the position indicator 1 of the present embodiment, theshield member 8 is interposed between the peripheral electrode 6 and thecenter electrode 7 to minimize the coupling between them. Accordingly,in the position indicator 1 of the present embodiment, the shield member8 is interposed to reduce the capacitance C2 between the peripheralelectrode 6 and the center electrode 7, by which the potential e can beincreased and the sensitivity can be raised efficiently.

The position indicator 1A of the embodiment described above isconfigured such that an alternating signal from the position detectionsystem 2A is received by the peripheral electrode 6 and an outputalternating signal after signal enhancement is fed back from the centerelectrode 7 to the position detection system 2A. However, the centerelectrode 7 may be used as the electrode for receiving an alternatingsignal from the position detection system 2A while the peripheralelectrode 6 is used as the electrode for feeding back the alternatingsignal after signal enhancement to the position detection system 2A.

It is to be noted that, as depicted in FIG. 9 , the position indicator1A wirelessly transmits pen pressure information, side switchinformation and identification information from the wirelesscommunication circuit 42 to the wireless communication circuit 25 of theposition detection system 2A. The pen pressure information, side switchinformation and identification information received by the wirelesscommunication circuit 25 are supplied to the control circuit 220A, bywhich they are transmitted, for example, to a host computer togetherwith detected position information. Also additional information from theposition indicator of the configuration type 1 is transmitted from thewireless communication circuit 42 to the position detection system in asimilar manner.

Position Indicator 1B of Configuration Type 3 and Corresponding PositionDetection System 2B

FIG. 10 is a view depicting an example of a circuit of principal part ofa position indicator 1B of the configuration type 3 and a correspondingposition detection system 2B. The position indicator 1B of theconfiguration type 3 transmits an alternating signal of the frequency f1as a stylus position signal and transmits all of pen pressureinformation, side switch information and identification information,which are additional information, from the wireless communicationcircuit 42 to a wireless communication circuit 25B of the positiondetection system 2B.

The position detection system 2B is configured from a sensor 20B, a penindication detection circuit 26B connected to the sensor 20B, and awireless communication circuit 25B. From the wireless communicationcircuit 25B of the position detection system 2B, an externalsynchronizing signal SYC is transmitted to the position indicator 1B asdescribed hereinabove after pairing with the position indicator 1B iscompleted.

The sensor 20B is configured from a first conductor group 211, aninsulating layer (not depicted) and a second conductor group 212 stackedin order from the lower layer side. The first conductor group 211includes a plurality of first conductors 211Y₁, 211Y₂, . . . , and211Y_(m) (m is an integer equal to or greater than 1) extending in ahorizontal direction (X axis direction) and disposed in parallel in apredetermined spaced relationship from each other in a Y axis direction.

Meanwhile, the second conductor group 212 includes a plurality of secondconductors 212X₁, 212X₂, . . . , and 212X_(n) (n is an integer equal toor greater than 1) extending in a direction intersecting with theextension direction of the first conductors 211Y₁, 211Y₂, . . . , and211Y_(m), in the present example, in a vertical direction (Y axisdirection) orthogonal to the extension direction of the first conductors211Y₁, 211Y₂, and 211Y_(m) and disposed in parallel in a predeterminedspaced relationship from each other in the X axis direction.

It is to be noted that, in the following description, where there is nonecessity to distinguish the first conductors 211Y₁, 211Y₂, . . . , and211Y_(m) from each other, each of the conductors is referred to as firstconductor 211Y. Similarly, where there is no necessity to distinguishthe second conductors 212X₁, 212X₂, . . . , and 212X_(n) from eachother, each of the conductors is referred to as second conductor 212X.

The pen indication detection circuit 26B is configured from a selectioncircuit 221 which is an input/output interface with the sensor 20B, anamplification circuit 222, a band-pass filter 223B, a detection circuit224, a sample hold circuit 225, an AD (Analog to Digital) conversioncircuit 226 and a control circuit 220B.

The selection circuit 221 selects one conductor from within each of thefirst conductors 211Y and the second conductors 212X in accordance witha control signal from the control circuit 220B. The conductors selectedby the selection circuit 221 are connected to the amplification circuit222, and a signal from the position indicator 1B is detected by theselected conductors and amplified by the amplification circuit 222. Anoutput of the amplification circuit 222 is supplied to the band-passfilter 223B, by which only a component of the frequency f1 of the signaltransmitted thereto from the position indicator 1B is extracted.

An output signal of the band-pass filter 223B is detected by thedetection circuit 224. An output signal of the detection circuit 224 issupplied to the sample hold circuit 225 and is sample-held at apredetermined timing with a sampling signal from the control circuit220B, whereafter it is converted into a digital value by the ADconversion circuit 226. Digital data from the AD conversion circuit 226is read and processed by the control circuit 220B.

The control circuit 220B acts to transmit control signals to the samplehold circuit 225, AD conversion circuit 226 and selection circuit 221 inaccordance with a program stored in an internal ROM thereof. Further,the control circuit 220B calculates position coordinates on the sensor20B indicated by the position indicator 1B from digital data from the ADconversion circuit 226.

FIG. 11 is a timing chart illustrating a signal transmitted from theposition indicator 1B of the configuration type 3 to the correspondingposition detection system 2B. As described hereinabove, from theposition indicator 1B of the configuration type 3, a signal, forexample, based on an alternating signal of the frequency f1 iscontinuously transmitted as a stylus position signal via the centerelectrode 7.

However, the position indicator 1B of the configuration type 3 of thepresent example utilizes the fact that the position indicator 1 of thepresent embodiment has a configuration capable of transmitting analternating signal of the frequency f1 and another alternating signal ofthe frequency f2 as a stylus position signal so that, if noise of afrequency equal to that of the stylus position signal exists, then thefrequency of the stylus position signal can be switched.

In particular, in the position indicator 1B of the configuration type 3of the present embodiment, the stylus position signal repeats one cycleincluding a continuous transmission period of a predetermined periodlength Ta and a pause period of another predetermined period length Tbas depicted in row A of FIG. 11 .

Further, the control circuit 220B of the position detection system 2Bdetects whether or not noise of a frequency equal to that of the stylusposition signal exists within a window interval provided by the pauseinterval of the predetermined period length Tb for detecting presence orabsence of noise as depicted in row B of FIG. 11 . If it is detectedthat noise of a frequency equal to that of the stylus position signalexists within the window interval, then the control circuit 220B of theposition detection system 2B notifies the position indicator 1B of thisvia the wireless communication circuit 25B.

If the reception circuit 422 of the wireless communication circuit 42 ofthe position indicator 1B receives the notification from the positiondetection system 2B, then it transfers the notification to the controlcircuit 410 of the signal transmission controlling circuit 41. Thecontrol circuit 410 of the signal transmission control circuit 41performs switching control of the switch circuit 414 in accordance withthe notification to perform switching from the state in which theoscillator 45 of the frequency f1 is selected to the state in which theoscillator 46 of the frequency f2 is selected. It is to be noted that,where the stylus position signal from the position indicator 1B when thenotification is received from the position detection system 2B is basedon the signal from the oscillator 46 of the frequency f2, the controlcircuit 410 performs, on the basis of a notification from the positiondetection system 2B, switching control of the switch circuit 414 toperform switching from the state in which the oscillator 46 of thefrequency f2 is selected to the state in which the oscillator 45 of thefrequency f1 is selected.

For example, when the stylus position signal from the position indicator1B is a signal of the frequency f1 as depicted in row A of FIG. 11 , ifnoise NR of the same frequency f1 exists as depicted in row C of FIG. 11, then the control circuit 220B of the position detection system 2Bdetects the noise NR within a window interval depicted in row B of FIG.11 and sends this fact to the position indicator 1B via the wirelesscommunication circuit 25B.

In the position indicator 1B, the control circuit 410 receives thisnotification from the position detection system 2B via the receptioncircuit 422 of the wireless communication circuit 42 and performsswitching control of the switch circuit 414 so that the frequency of thestylus position signal is switched from the frequency f1 to thefrequency f2 as depicted in row D of FIG. 11 . Accordingly, even ifnoise of a frequency equal to that of the stylus position signal existsaround the position detection system 2B, it is possible to prevent theinfluence of the noise by switching of the frequency of the stylusposition signal.

It is to be noted that, in the position detection system 2B, in order toallow compatibility with both of stylus position signals of thefrequency f1 and the frequency f2, the band-pass filter 223B has a statein which it uses a pass frequency band having a center frequency same asthe frequency f1 and another state in which it uses another passfrequency band having a different center frequency same as the frequencyf2, and is configured for switching of the pass frequency band betweenthe two pass frequency bands.

Position Indicator 1C of Configuration Type 4 and Corresponding PositionDetection System 2C

FIG. 12 is a view depicting an example of a circuit of part of aposition indicator 1C of the configuration type 4 and a correspondingposition detection system 2C. The position indicator 1C of theconfiguration type 4 transmits an alternating signal of the frequency f2as a stylus position signal and transmits pen pressure information andside switch information which are examples of additional informationimportant to a position indicator to the position detection system 2Cvia the center electrode 7 together with the stylus position signal.Further, the position indicator 1C transmits identification informationof additional information from the wireless communication circuit 42 toa wireless communication circuit 25C of the position detection system2C.

The position detection system 2C is configured from a sensor 20C, a penindication detection circuit 26C connected to the sensor 20C and awireless communication circuit 25C as depicted in FIG. 12 . From thewireless communication circuit 25C of the position detection system 2C,an external synchronizing signal SYC is transmitted to the positionindicator 1C as described hereinabove after pairing with the positionindicator 1C is completed.

The sensor 20C has, in the present example, a configuration that is thesame as that of the sensor 20B of the position detection system 2B.Further, the pen indication detection circuit 26C has a configurationthat is the same as that of the pen indication detection circuit 26Bexcept a band-pass filter 223C and a control circuit 220C.

The band-pass filter 223C of the position detection system 2Ccorresponding to the position indicator 1C of the configuration type 4has, in the present example, a pass frequency band whose centerfrequency is the frequency f2. Further, the control circuit 220Cincludes a function for detecting pen pressure information and sideswitch information sent thereto together with a stylus position signal.

In the position indicator 1C of the configuration type 4 of the presentexample, the center electrode transmission signal generation circuit 412repetitively outputs a signal of a pattern whose one cycle includes acontinuous transmission period and a transmission data period under thecontrol of the control circuit 410. Row A of FIG. 13 depicts an exampleof a control signal supplied from the control circuit 410 of theposition indicator 1C to the center electrode transmission signalgeneration circuit 412. The center electrode transmission signalgeneration circuit 412 continuously transmits, within the fixed periodwithin which the high level of the control signal of row A of FIG. 13 ismaintained, an oscillation signal of the frequency f2 as a burst signalas depicted in row B of FIG. 13 (continuous transmission period of row Cof FIG. 13 ).

The length of the continuous transmission period is a time length withinwhich the pen indication detection circuit 26C of the position detectionsystem 2C can detect an indicated position on the sensor circuit 20C bythe position indicator 1C and is a time length within which, forexample, all of the first conductors 211Y and the second conductors 212Xcan be scanned once or more, preferably by a plural number of times.

Within the continuous transmission period, the control circuit 410 ofthe position indicator 1C calculates the pen pressure applied to thecenter electrode 7 on the basis of the capacitance of the variablecapacitance of the pen pressure detection circuit 9 and determinesinformation of the calculated voltage value as a value of a plurality ofbits (binary code). Further, the control circuit 410 generates on/offinformation of the side switch 43 as side switch information and asinformation of one bit or a plurality of bits.

Then, the control circuit 410 controls, within a transmission dataperiod after an end of a continuous transmission period, the controlsignal to the high level or the low level in a predetermined cycle (Td)as depicted in row A of FIG. 13 to modulate an alternating signal of thefrequency f2 by ASK (Amplitude Shift Keying). The control circuit 410may generate an OOK (On Off Keying) signal in place of the ASKmodulation.

At this time, within a first predetermined period (Td) after thecontinuous transmission period, the control circuit 410 controls thecontrol signal to the high level without fail and uses the signal as astart signal of row C of FIG. 13 . This start signal is a timing signalfor making it possible for the pen indication detection circuit 26C ofthe position detection system 2C to decide later data transmittingtimings accurately. It is to be noted that, in place of this startsignal, a burst signal within a continuous transmission period can beutilized as a timing signal.

The center electrode transmission signal generation circuit 412 of theposition indicator 1C successively transmits pen pressure information ofa plurality of bits or side switch information of a plurality of bitsfollowing the start signal within a transmission data period under thecontrol of the control circuit 410 described above. In this case, asdepicted in rows A and B of FIGS. 13 , when the transmission data(binary code) is “0,” the control signal (row A of FIG. 13 ) iscontrolled to the low level so that no alternating signal is outputted,but when the transmission data (binary code) is “1,” the control signalis controlled to the high level so that an alternating signal isoutputted thereby to perform ASK modulation.

In the pen indication detection circuit 26C of the position detectionsystem 2C, the control circuit 220C detects an indicated position by theposition indicator 1C from a reception signal within a continuoustransmission period similarly as in the case of the position detectionsystem 2B described hereinabove. Then, the control circuit 220C waitsuntil the continuous transmission period comes to an end and then, if astart signal after the end of the continuous transmission period isdetected, performs actions to detect data of the pen pressureinformation and the side switch information within the transmission dataperiod and restore the data. Then, the control circuit 220C outputs,together with identification information received via the wirelesscommunication circuit 25C, the detection information of the indicatedposition by the position indicator 1C, pen pressure information and sideswitch information to a host computer or the like.

It is to be noted that also the position indicator 1C of theconfiguration type 4 may be configured such that it can performswitching of the frequency of the stylus position signal similarly tothe position indicator 1B of the configuration type 3 so that theinfluence of noise can be reduced. In this case, also the band-passfilter 223C and the control circuit 220C of the position detectionsystem 2C are configured such that they have functions similar to thoseof the band-pass filter 223B and the control circuit 220B of theposition detection system 2B corresponding to the configuration type 3.

Position Indicator 1D of Configuration Type 5 and Corresponding PositionDetection System 2D

FIG. 14 is a view depicting an example of a circuit of part of aposition indicator 1D of the configuration type 5 and a correspondingposition detection system 2D. The position indicator 1D of theconfiguration type 5 transmits an alternating signal of the frequency f2as a stylus position signal and transmits all additional information, inthe present example, all of pen pressure information, side switchinformation and identification information ID1, to the positiondetection system 2D via the center electrode 7 together with the stylusposition signal.

The position detection system 2D includes, as depicted in FIG. 14 , asensor 20D, a pen indication detection circuit 26D connected to thesensor 20D, and a wireless communication circuit 25D. From the wirelesscommunication circuit 25D of the position detection system 2D, anexternal synchronizing signal SYC is transmitted to the positionindicator 1D as described hereinabove after pairing with the positionindicator 1D is completed.

The sensor 20D has, in the present example, a configuration same as thatof the sensor 20B of the position detection system 2B. Further, the penindication detection circuit 26D has a configuration same as that of thepen indication detection circuit 26C including a band-pass filter 223Dexcept a control circuit 220D. In particular, the band-pass filter 223Dhas, in the present example, a pass frequency band whose centerfrequency is the frequency f2. Further, the control circuit 220Dincludes a function for detecting pen pressure information, side switchinformation and identification information ID1 sent thereto togetherwith a stylus position signal.

Also in the position indicator 1D of the configuration type 5 of thepresent example, the center electrode transmission signal generationcircuit 412 repetitively outputs a signal of a pattern whose one cycleincludes a continuous transmission period and a transmission data periodas depicted in FIG. 15 under the control of the control circuit 410similarly as in the position indicator 1C of the configuration type 4described hereinabove.

Row A of FIG. 15 depicts an example of a control signal supplied fromthe control circuit 410 of the position indicator 1D to the centerelectrode transmission signal generation circuit 412. The centerelectrode transmission signal generation circuit 412 of the positionindicator 1D of the present example continuously transmits, within thecontinuous transmission period, an oscillation signal of the frequencyf2 as a burst signal as depicted in row B of FIG. 15 under the controlof the control signal of row A of FIG. 15 . On the other hand, withinthe transmission data period, the center electrode transmission signalgeneration circuit 412 transmits pen pressure information, side switchinformation and identification information ID1 as an ASK signal to theposition detection system 2D via the center electrode 7 as depicted inrows B and C FIGS. 15 .

The control circuit 220D of the position detection system 2D detects, onthe basis of the burst signal within the continuous transmission period,the position on the sensor 20D indicated by the position indicator 1Dand detects and restores, within the transmission data period, the penpressure information, side switch information and identificationinformation ID1.

Further, in this example, the position indicator 1D transmitsidentification information ID2 from the wireless communication circuit42 to the wireless communication circuit 25D of the position detectionsystem 2D to make receiving and transmitting signals between theposition indicator 1D and the position detection system 2D more secure.In this case, the identification information ID1 and the identificationinformation ID2 are made same information (ID1=ID2). The control circuit220D compares the identification information ID2 acquired via thewireless communication circuit 25D and the identification informationID1 received and detected via the center electrode 7 with each other,and determines, only when they coincide with each other, the signalacquired from the position indicator 1D as valid and processes thesignal.

Then, when the control circuit 220D determines that the signal acquiredfrom the position indicator 1D is valid, the control circuit 220Doutputs the detection information of the indicated position by theposition indicator 1D and the pen pressure information, side switchinformation and identification information ID1 to the host computer orthe like.

Other Embodiments Other Example of Capacitive Coupling

The plurality of configuration types of a position indicator describedhereinabove are examples, and it is a matter of course that theconfiguration type of a position indicator is not limited theconfiguration types connected here. For example, while, in the positionindicator of the active type described hereinabove, a signal istransmitted only from the center electrode 7, the configuration type ofa position indicator configured such that, in order to make it possibleto detect an inclination angle or a rotational angle of a positionindicator on a position detection system, the peripheral electrode 6 isdivided into a plurality of peripheral electrodes and, from each of theplurality of divisional peripheral electrodes, a signal for making itpossible to identify the divisional peripheral electrode is transmittedis made one configuration type.

Example of Electromagnetic Coupling

Further, while the embodiment described above is a position indicatorand a position detection system of the capacitive coupling type, thepresent disclosure can be applied also to a position indicator and aposition detection system of the electromagnetic coupling type.

FIG. 16 depicts an example of a configuration of a position indicator100 of the electromagnetic coupling type according to the presentdisclosure and corresponds to the conceptual block diagram of FIG. 1which depicts the position indicator 1 of the embodiment describedhereinabove.

As depicted in FIG. 16 , the position indicator 100 of the presentembodiment includes, in a cylindrical housing 103 made of an insulator,for example, a resin, a signal transmission controlling circuit 141, awireless communication circuit 142, a side switch 143, an ID memory 144and an oscillator 145 and further includes a pen pressure detectioncircuit 109. Further, a battery 105 is provided as a supply source of apower supply voltage to the signal transmission controlling circuit 141,wireless communication circuit 142, side switch 143, ID memory 144,oscillator 145 and so forth in the housing 103. The signal transmissioncontrolling circuit 141 includes a pen type decision circuit 1411.

To the pen pressure detection circuit 109, a core member 107 extendingthrough a ferrite core 110 is coupled, and the pen pressure detectioncircuit 109 detects a pen pressure applied to the core member 107 as acapacitance of a variable capacitor configured from the pen pressuredetection circuit 109. A coil 111 is wound on the ferrite core 110 andis connected at the opposite terminals thereof to the signaltransmission control circuit 141. Further, between the oppositeterminals of the coil 111, a capacitor 112 cooperating with the coil 111to configure a resonance circuit is connected.

To the signal transmission controlling circuit 141, the wirelesscommunication circuit 142, side switch 143, ID memory 144 and oscillator145 are connected similarly as in the position indicator 1 of theembodiment described hereinabove, and also the variable capacitorconfigured from the pen pressure detection circuit 109 is connected tothe signal transmission controlling circuit 141.

In the position indicator 100, the signal transmission control circuit141 controls selection of a signal to be transmitted via a resonancecircuit including the coil 111 and the capacitor 112 and controlsselection regarding whether additional information such as pen pressureinformation, side switch information and identification information isto be transmitted from the wireless communication circuit 142 or to betransmitted as a signal from the resonance circuit.

In particular, in the case of the position indicator 100 of the presentembodiment, the resonance circuit configures a second transmissioncircuit and the transmission circuit of the wireless communicationcircuit 142 configures a first transmission circuit. Further, thereception circuit of the wireless communication circuit 142 configures areception circuit for receiving pen type information from the positiondetection system. The pen type information received from the positiondetection system by the reception circuit of the wireless communicationcircuit 142 is supplied to the pen type decision circuit 1411 of thesignal transmission control circuit 141. Also in the present embodiment,the pen type decision circuit 1411 can be configured, though notdepicted, from a pen type discrimination processing circuit and a pentype table memory.

The signal transmission controlling circuit 141 of the positionindicator 100 of the present embodiment receives pen type informationfrom the position detection system and can decide the pen type bydetermining the pen type with the pen type decision circuit 1411 toconfigure, for example, such position indicators 100A, 100B and 100C ofthree different configuration types 6, 7 and 8 as depicted in FIGS. 17A,17B, and 17C, respectively.

If pen type information received from the position detection system viathe reception circuit of the wireless communication circuit 142 of theposition indicator 100 is the configuration type 6, then such a positionindicator 100A as depicted in FIG. 17A is configured by the signaltransmission controlling circuit 141. In particular, in thisconfiguration type 6, the variable capacitor configured from the penpressure detection circuit 109 is connected in parallel to a parallelresonance circuit configured from the coil 111 and the capacitor 112,and further, a serial circuit of the side switch 143 and a capacitor 113is connected.

Further, a sensor of a position detection system 200A which is usedtogether with the position indicator 100A of the configuration type 6and sends the configuration type 6 as pen type information to theposition indicator 100A is configured such that, though not depicted, aplurality of loop coils are arrayed in an X direction and a Y directionwhich are orthogonal to each other such that a transmission signal(alternating signal) of frequency fa is transmitted from the loop coilsto the position indicator 100A.

In the position indicator 100A, an alternating signal from the positiondetection system 200A is received by the resonance circuit throughelectromagnetic coupling, and then the alternating signal is fed backfrom the resonance circuit to the position detection system 200A. In theposition detection system 200A, the position indicated by the positionindicator 100A is detected from the position of a loop coil from whichthe alternating signal is transmitted and the position of another loopcoil which receives the feedback signal from the position indicator100A.

In this case, since the feedback signal from the position indicator 100Avaries as the resonance frequency of the resonance circuit variesdepending upon the value of the capacitance of the variable capacitorconfigured from the pen pressure detection circuit 109, the positiondetection system 200A detects pen pressure information from thevariation of the frequency (or from the variation of the phase).

Further, since the capacitor 113 is placed into a connection state or adisconnection state to or from the resonance circuit in response toswitching on and off of the side switch 143, the resonance frequency ofthe resonance circuit varies in response to switching on and off of theside switch 143. The position detection system 200A detects side switchinformation corresponding to switching on and off of the side switch 143from the variation of the frequency (or from the variation of the phase)of the feedback signal from the position indicator 100A.

It is to be noted that the position indicator 100A of the configurationtype 6 transmits identification information to the wirelesscommunication circuit of the position detection system 200A via thetransmission function circuit of the wireless communication circuit 142.

If the pen type information received from the position detection systemvia the reception circuit of the wireless communication circuit 142 ofthe position indicator 100 is the configuration type 7, then the signaltransmission controlling circuit 141 configures such a positionindicator 100B as depicted in FIG. 17B. In particular, in theconfiguration type 7, the parallel resonance circuit is configured froma coil 111 and a capacitor 112. All of pen pressure information, sideswitch information and identification information are transmitted to thewireless communication circuit of a position detection system 200B viathe transmission circuit of the wireless communication circuit 142.

The sensor circuit of the position detection system 200B which is usedtogether with the position indicator 100B of the configuration type 7and sends the configuration type 7 as pen type information to theposition indicator 100B has a configuration same as that of the sensorof the position detection system 200A. Thus, a transmission signal(alternating signal) of the frequency fa is transmitted from a loop coilto the position indicator 100B.

In the position indicator 100B, an alternating signal from the positiondetection system 200B is received by the resonance circuit throughelectromagnetic coupling and is thereafter fed back from the resonancecircuit to the position detection system 200B similarly as in the caseof the position indicator 100A. The position detection system 200Bdetects a position indicated by the position indicator 100B in a similarmanner as in the position detection system 200A.

The position detection system 200B of the configuration type 7 does notinclude a function for monitoring a variation of the frequency or thephase of a feedback signal to detect additional information. Theposition detection system 200B decodes additional information receivedvia the wireless communication circuit to acquire pen pressureinformation, side switch information and identification information.

If the pen type information received from the position detection systemvia the reception circuit of the wireless communication circuit 142 ofthe position indicator 100 is the configuration type 8, then the signaltransmission controlling circuit 141 configures such a positionindicator 100C as depicted in FIG. 17C. In particular, in the positionindicator 100C of the configuration type 8, the parallel resonancecircuit configured from the coil 111 and the capacitor 112 is coupled tothe oscillator 145 to configure an oscillation circuit 145S. Anoscillation signal from the oscillation circuit 145S is transmitted to aposition detection system 200C via the parallel resonance circuitconfigured from the coil 111 and the capacitor 112.

Further, pen pressure information, side switch information andidentification information are all transmitted to the wirelesscommunication circuit of the position detection system 200C via thetransmission circuit of the wireless communication circuit 142.

The sensor of the position detection system 200C which is used togetherwith the position indicator 100C of the configuration type 8 and sendsthe configuration type 8 as pen type information is configured suchthat, though not depicted, a plurality of loop coils are arrayed in an Xdirection and a Y direction orthogonal to each other.

The position detection system 200C receives an alternating signaltransmitted thereto from the position indicator 100C by a loop coilthrough electromagnetic coupling. Further, the position detection system200C detects the position indicated by the position indicator 100C fromthe positions of the loop coil in the X direction and the Y direction bywhich the alternating signal is received.

It is to be noted that also the configuration types 6 to 8 describedabove are examples and various other types are available as theconfiguration type of the position indicator and the position detectionsystem of the electromagnetic coupling type, and it is a matter ofcourse that the position indicator of the present disclosure can beconfigured so as to match with those various configuration types. Forexample, while, in the configurations 6 to 8 described above,identification information is not transmitted via the resonance circuit,also it is possible to configure a configuration type wherein theresonance action of the resonance circuit or the switching on/off of theresonance action of the oscillation circuit 145S is controlled totransmit identification information as an ASK modulation signal or anOOK signal from the core member 107 side.

Example of Hybrid Position Indicators of Both of Capacitive CouplingType and Electromagnetic Coupling Type

FIGS. 18 and 18B are views depicting major part of a position indicator1E of a configuration type which includes both of an active capacitivepen of the capacitive coupling type and an electronic pen of theelectromagnetic coupling type, and FIG. 18A is a view illustrating aconfiguration portion of the center electrode 7 side having aconductivity and FIG. 18B is a view when the position indicator 1E isviewed in an axial direction thereof from the tip end side of the centerelectrode 7. Further, FIG. 19 is a block diagram depicting an example ofa configuration of an electronic circuit of the position indicator 1E ofthe present example as depicted in FIGS. 18A and 18B.

In the present position indicator 1E, the peripheral electrode, which ismade of a conductor provided around an opening in which the centerelectrode 7 is inserted, of the housing 3 is formed from six divisionalportions as divisional peripheral electrodes 6A, 6B, 6C, 6D, 6E and 6F.The divisional peripheral electrodes 6A to 6F are provided in a mutuallyelectrically isolated separated state as depicted in FIGS. 18A and 18B.

The center electrode 7 is fitted in a pen pressure detection circuit 9through a through-hole provided in the ferrite core 110 and isconfigured such that it receives a signal from a signal transmissioncontrolling circuit configured on a board 40. A coil 111 is wound on theferrite core 110, and a capacitor 112 is connected in parallel to thecoil 111 via a switch circuit 114 as depicted in FIG. 19 .

In the case of the configuration type of an active capacitive pen of thecapacitive coupling type, the switch circuit 114 is controlled off by acontrol signal from the control circuit 410, and the parallel resonancecircuit configured from the coil 111 and the capacitor 112 is notconfigured. Further, in the case of the configuration type of the activecapacitive pen of the capacitive coupling type, a signal from the signaltransmission controlling circuit is transmitted via the center electrode7, whereupon the divisional peripheral electrodes 6A to 6F are used as ashield electrode.

On the other hand, in the case of the configuration type of theelectronic pen of the electromagnetic coupling type, the switch circuit114 is switched on by a control signal from the control circuit 410 andthe parallel resonance circuit configured from the coil 111 and thecapacitor 112 is configured. By the parallel resonance circuit, a signalfrom the position detection system 2 is received and fed back by theelectromagnetic coupling to transmit a stylus position signal to theposition detection system 2 similarly as in the case of FIG. 16 . Atthis time, since the divisional peripheral electrodes 6A to 6F areseparated from each other, it is possible to prevent magnetic fluxes forelectromagnetic coupling between the parallel resonance circuit and theposition detection system 2 from being shielded.

Other Embodiments or Modifications

In the pen pressure detection circuits 9 and 109 of the embodimentsdescribed above, a variable capacitor is used wherein a dielectric issandwiched by the first electrode and the second electrode and one ofthe first electrode and the second electrode is mounted for movement inan axial direction in response to a pen pressure such that thecapacitance thereof is variable in response to the pen pressure.However, the configuration of the pen pressure detection circuit is notlimited to this. For example, it is possible to configure the penpressure detection circuit 9 using such a semiconductor element whosecapacitance is variable in response to a pen pressure as disclosed inJapanese Patent Laid-Open No. 2013-161307. Alternatively, the penpressure detection circuit may be configured using a structure or anelement having not a capacitance but an inductance value or a resistancevalue which is variable in response to a pen pressure.

Further, the additional information is not limited to pen pressureinformation, side switch information, identification information or thelike as described above, but various other information such as, forexample, capacity information of a battery can be used as additionalinformation.

Further, while the driving power supply for the position indicator inthe foregoing description of the embodiments is a battery, a capacitorfor accumulating a power supply voltage may be provided in the positionindicator such that the capacitor is used as a driving power supply. Inthis case, the configuration for accumulating the power supply voltageinto the capacitor may be a configuration of a charging circuit forreceiving electric power energy from the outside through electromagneticinduction or electric field coupling and charging the capacitor, orfurther, a charging terminal may be provided for the position indicatorsuch that charging current is supplied from a charging apparatus forexclusive use via the charging terminal. The electric power energy fromthe outside (electromagnetic energy or electric field energy) may besupplied from the position detection apparatus to the position indicatoror may be supplied from an electric power supplying apparatus forexclusive use.

Further, while the position indicators in the embodiments describedabove include two transmission circuits of a center electrode and awireless communication circuit, they may otherwise include three or moretransmission circuits.

It is to be noted that, in the description of the position indicator ofeach of the embodiments described above, if the position indicator isoperated to move to the proximity of or contact with the sensor of theposition detection system, then the position indicator automaticallycomes to have a configuration type compatible with the positiondetection system. However, the position indicator may be configured soas to be set to a selected and desired configuration type by configuringthe position indicator so as to communicate not with the positiondetection system but with an outer device such as a personal computerwhich can communicate with the wireless communication circuit of theposition indicator and selecting the desired configuration type throughthe outer device such as a personal computer.

Alternatively, the position indicator may be configured such that aswitch for switching setting of a configuration type may be provided onthe position indicator such that the position indicator is set to adesired configuration type by a switching operation by the switch forswitching setting. In particular, the example of FIG. 16 is configuredsuch that a pushbutton switch 146 which can be operated by the user isprovided on the housing 103 such that a depression operation signal ofthe pushbutton switch 146 is supplied to the signal transmissioncontrolling circuit 141. In this case, the signal transmissioncontrolling circuit 141 performs control for changing the configurationtype, for example, every time the pushbutton switch 146 is depressed bythe user. It is to be noted that, also in the example of FIG. 1 , apushbutton switch may be provided similarly.

DESCRIPTION OF REFERENCE SYMBOLS

1, 1A to 1E, 100A to 100C . . . Position indicator, 2, 2A to 2D, 200A to200C . . . Position detection system, 3 . . . Housing, 31 . . .Insulator portion, 32 . . . Conductor portion, 5 . . . Battery, 6 . . .Peripheral electrode 7 . . . Center electrode, 8 . . . Shield member, 9. . . Pen pressure detection circuit, 40 . . . Printed circuit board, 41. . . Signal transmission control circuit, 42 . . . Wirelesscommunication circuit, 43 . . . Side switch, 44 . . . ID memory, 45, 46. . . Oscillator, 48 . . . Power supply switch, 410 . . . Controlcircuit, 411 . . . Pen type decision circuit

The invention claimed is:
 1. A position indicator for communicating witha position detection system, the position indicator comprising: a signalgeneration circuit which, in operation, generates a position signal; anadditional information generation circuit which, in operation, generatesadditional information; a first transmission circuit which, inoperation, transmits the position signal to the position detectionsystem via capacitive coupling; a second transmission circuit differentfrom the first transmission circuit; and a control circuit which, inoperation: makes a first selection in which the first transmissioncircuit is selected and the additional information and the positionsignal are transmitted from the first transmission circuit to theposition detection system, and makes a second selection in which thesecond transmission circuit is selected and the additional informationis transmitted from the second transmission circuit to the positiondetection system while the position signal is transmitted from the firsttransmission circuit to the position detection system.
 2. The positionindicator according to claim 1, wherein the control circuit, inoperation, controls at least a transmission timing of the positionsignal based on a signal transmitted from the position detection systemand received by the position indicator.
 3. The position indicatoraccording to claim 1, comprising: a pen-shaped housing; a centralelectrode extending from one end in an axial direction of the pen-shapedhousing; and a pressure detector configured to detect a pressure appliedto the central electrode; wherein, the first transmission circuittransmits the position signal via the central electrode, and in responseto the selection of the second transmission circuit, the control circuittransmits information regarding the pressure detected by the pressuredetector from the second transmission circuit to the position detectionsystem.
 4. The position indicator according to claim 1, comprising: apen-shaped housing; a central electrode extending from one end in anaxial direction of the pen-shaped housing; and a storage includingidentification information of the position indicator; wherein, the firsttransmission circuit transmits the position signal via the centralelectrode, and in response to the selection of the second transmissioncircuit, the control circuit transmits the identification informationfrom the second transmission circuit to the position detection system.5. The position indicator according to claim 1, comprising: a pen-shapedhousing; a central electrode extending from one end in an axialdirection of the pen-shaped housing; and a switch configured to receiveuser operation thereon; wherein, the first transmission circuittransmits the position signal via the central electrode, and in responseto the selection of the second transmission circuit, the control circuittransmits information regarding the user operation on the switch fromthe second transmission circuit to the position detection system.
 6. Theposition indicator according to claim 1, wherein the control circuit, inoperation, controls a transmission timing of the additional informationbased on a signal transmitted from the position detection system andreceived by the position indicator.
 7. The position indicator accordingto claim 1, wherein, in response to the selection of the secondtransmission circuit, the control circuit transmits the additionalinformation from the second transmission circuit to the positiondetection system, and the control circuit controls a transmission timingof the additional information based on a signal transmitted from theposition detection system and received by the position indicator.
 8. Theposition indicator according to claim 1, wherein the control circuit, inoperation, controls a transmission frequency of the position signalbased on a signal transmitted from the position detection system andreceived by the position indicator.
 9. The position indicator accordingto claim 1, wherein the control circuit, in operation, controls atransmission cycle of the position signal based on a signal transmittedfrom the position detection system and received by the positionindicator.
 10. A position indicator for communicating with a positiondetection system, the position indicator comprising: a pen-shapedhousing; a signal generation circuit which, in operation, generates aposition signal; an additional information generation circuit which, inoperation, generates additional information; a first transmissioncircuit which, in operation, transmits the position signal to theposition detection system via capacitive coupling; a second transmissioncircuit different from the first transmission circuit; a centralelectrode extending from one end in an axial direction of the pen-shapedhousing; a peripheral electrode disposed adjacent to the centralelectrode; and a control circuit which, in operation: controlstransmission of the position signal, via the central electrode or theperipheral electrode, to the position detection system; makes a firstselection in which the first transmission circuit is selected and theadditional information and the position signal are transmitted from thefirst transmission circuit to the position detection system; and makes asecond selection in which the second transmission circuit is selectedand the additional information is transmitted from the secondtransmission circuit to the position detection system while the positionsignal is transmitted from the first transmission circuit to theposition detection system.
 11. The position indicator according to claim10, wherein the control circuit, in operation, controls at least atransmission timing of the position signal based on a signal transmittedfrom the position detection system and received by the positionindicator.
 12. The position indicator according to claim 10, comprising:a pressure detector configured to detect a pressure applied to thecentral electrode; wherein, in response to the selection of the secondtransmission circuit, the control circuit transmits informationregarding the pressure detected by the pressure detector from the secondtransmission circuit to the position detection system.
 13. The positionindicator according to claim 10, comprising: a storage includingidentification information of the position indicator; wherein, inresponse to the selection of the second transmission circuit, thecontrol circuit transmits the identification information from the secondtransmission circuit to the position detection system.
 14. The positionindicator according to claim 10, comprising: a switch configured toreceive user operation thereon; wherein, in response to the selection ofthe second transmission circuit, the control circuit transmitsinformation regarding the user operation on the switch from the secondtransmission circuit to the position detection system.
 15. The positionindicator according to claim 10, wherein the control circuit, inoperation, controls a transmission timing of the additional informationbased on a signal transmitted from the position detection system andreceived by the position indicator.
 16. The position indicator accordingto claim 10, wherein the control circuit, in operation, controls atransmission frequency of the position signal based on a signaltransmitted from the position detection system and received by theposition indicator.
 17. The position indicator according to claim 10,wherein the control circuit, in operation, controls a transmission cycleof the position signal based on a signal transmitted from the positiondetection system and received by the position indicator.
 18. A positionindicator for communicating with a position detection system, theposition indicator comprising: a signal generation circuit which, inoperation, generates a position signal; an additional informationgeneration circuit which, in operation, generates additionalinformation; a transmission circuit which, in operation, transmits theposition signal to the position detection system via capacitivecoupling; a wireless communication circuit which, in operation,transmits and receives signals to and from the position detection systemvia a short-range wireless communication technology different from thecapacitive coupling; and a control circuit which, in operation: makes afirst selection in which the transmission circuit is selected and theadditional information and the position signal are transmitted from thetransmission circuit to the position detection system, and makes asecond selection in which the wireless communication circuit is selectedand the additional information is transmitted from the wirelesscommunication circuit to the position detection system while theposition signal is transmitted from the transmission circuit to theposition detection system.
 19. The position indicator according to claim18, wherein, the control circuit, in response to establishment of acommunication link between the wireless communication circuit and theposition detection system, controls a transmission timing of theadditional information based on a signal transmitted from the positiondetection system and received by the wireless communication circuit, andin response to the selection of the wireless communication circuit, thecontrol circuit transmits the additional information from the wirelesscommunication circuit to the position detection system.
 20. The positionindicator according to claim 18, wherein the control circuit, inresponse to establishment of a communication link between the wirelesscommunication circuit and the position detection system, controlstransmission of the position signal, from the transmission circuit tothe position detection system, based on a signal transmitted from theposition detection system and received by the wireless communicationcircuit.
 21. The position indicator according to claim 20, wherein thecontrol circuit, in operation, controls at least a transmission timingof the position signal based on the signal transmitted from the positiondetection system and received by the wireless communication circuit. 22.The position indicator according to claim 20, wherein the controlcircuit, in operation, controls a transmission frequency of the positionsignal based on the signal transmitted from the position detectionsystem and received by the wireless communication circuit.
 23. Theposition indicator according to claim 20, wherein the control circuit,in operation, controls a transmission cycle of the position signal basedon the signal transmitted from the position detection system andreceived by the wireless communication circuit.
 24. The positionindicator according to claim 18, wherein the short-range wirelesscommunication technology is a Bluetooth® wireless communicationtechnology.
 25. The position indicator according to claim 18, furthercomprising: a pen-shaped housing.